Carbon Dioxide Recovery System

The present disclosure relates to a carbon dioxide recovery system.

Patent Document 1 discloses a device that removes carbon dioxide in air using an adsorbent capable of adsorbing carbon dioxide.

Patent Document 1: Japanese Unexamined Patent Application, First Publication No. 2020-131166.

It is required to improve a recovery efficiency of carbon dioxide by an adsorbent.

In view of the above circumstances, the present disclosure is to provide a carbon dioxide recovery system capable of improving a recovery efficiency of carbon dioxide.

One aspect of the carbon dioxide recovery system according to the present disclosure includes a plurality of outdoor units of an air conditioning system; an adsorbent that are configured to adsorb carbon dioxide; a plurality of first containers that are disposed at positions in which at least part of an air flow generated by the plurality of outdoor units reaches, that are configured to accommodate the adsorbent therein, and that have air permeability; a separation device that is connected to the plurality of first containers and that is configured to separate carbon dioxide from the adsorbent which has adsorbed the carbon dioxide; and a recovery device that is configured to recover the carbon dioxide separated by the separation device, in which the number of the plurality of first containers is greater than the number of separation devices.

Another aspect of the carbon dioxide recovery system according to the present disclosure includes a plurality of outdoor units of an air conditioning system; an adsorbent that is configured to adsorb carbon dioxide; a container that is disposed above the plurality of outdoor units, that is configured to accommodate the adsorbent therein, and that has air permeability; a separation device that is connected to the container and that is configured to separate carbon dioxide from the adsorbent which has adsorbed the carbon dioxide; and a recovery device that is configured to recover the carbon dioxide separated by the separation device, in which the separation device is disposed above the recovery device.

According to the present disclosure, it is possible to provide a carbon dioxide recovery system capable of improving a recovery efficiency of carbon dioxide.

Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. The scope of the present disclosure is not limited to the following embodiment, and can be changed in any way within the scope of technical ideas of the present disclosure.

is a block diagram of a carbon dioxide recovery systemaccording to Embodiment 1.is a plan view schematically showing the carbon dioxide recovery system.is a cross-sectional view taken along line A-A of.

The carbon dioxide recovery systemrecovers carbon dioxide from air. The carbon dioxide recovery systemis installed, for example, on the roof of a building (such as an office building or an apartment). The carbon dioxide recovery systemmay also be installed in an open space next to an office building, in the courtyard of an apartment, in a desert, or in similar locations.

The carbon dioxide recovery systemincludes a plurality of outdoor unitsof an air conditioning system, an adsorbent, a plurality of first containers, a first adsorbent pipe, a separation device, a recovery device, and a renewable energy device.

The air conditioning system regulates air inside the building (indoors). In the present embodiment, the air conditioning system is, for example, a multi-air conditioner for the office building. The air conditioning system includes a plurality of outdoor unitsinstalled outdoors and a plurality of indoor units (not shown) installed indoors. In the air conditioning system, the refrigerant circulates between the outdoor unitand the indoor units.

As shown in, the outdoor unitincludes a casing, a heat exchanger, and a blower(see).

The casinghas a rectangular parallelepiped shape with four side surfaces, a top surface, and a bottom surface. A blowing portis formed on the top surface of the casing. Among the four side surfaces of the casing, three side surfaces are formed with intake ports.

The heat exchangeris disposed inside the casing. The heat exchangerperforms heat exchange between the refrigerant and the outside air (air). In a plan view, the heat exchangerhas a substantially U shape. The heat exchangeris disposed along the three side surfaces of the casingin which the intake portsare formed.

The bloweris disposed inside the casing. The blowerdirects air from the inside of the outdoor unitto the outside. When the bloweris driven, air is sucked into the casingfrom the intake port. The air sucked into the casingpasses through the heat exchangerand is blown out from the blowing portto the outside of the casing. The air is blown upward from the blowing port.

In the present embodiment, the plurality of outdoor unitsare arranged in two rows (a first row and a second row). The first row and the second row are parallel to each other. The outdoor unitsin the first row and the outdoor unitsin the second row are disposed such that the side surfaces of the casings, in which the heat exchangersare not disposed (that is, the side surfaces without the intake ports), face each other.

The disposition of the plurality of outdoor unitsis not limited to this. The plurality of outdoor unitsmay be arranged in a single row. The plurality of outdoor unitsmay be arranged in two or more rows.

In addition, among the four side surfaces of the casing, the intake portmay be formed on the entire surface of three side surfaces and on half of the remaining one side surface. In this case, among the four side surfaces of the casing, the heat exchangeris disposed along the entire surface of three side surfaces and along half of the remaining one side surface. Among the four side surfaces of the casing, the outdoor unitin the first row and the outdoor unitin the second row are disposed such that the side surfaces with the smallest area in which the heat exchangeris disposed (that is, the side surfaces with the smallest area in which the intake portis formed), face each other.

The adsorbent includes a material capable of adsorbing carbon dioxide. Examples of a material capable of adsorbing carbon dioxide include amine, zeolite, silica gel, diatomaceous earth, alumina, activated carbon, and the like. A plurality of materials may be selected and adopted from the above, or a material other than the above may be adopted. The adsorbent may have a granular shape (for example, bead shape (spherical) or pellet shape (cylindrical)). Alternatively, a powdery adsorbent may be adopted. In this case, the powdery adsorbent may be carried on a surface of a base material. The base material may have, for example, a honeycomb shape.

The first containeris a container capable of accommodating the adsorbent therein. The first containeris attached to the outdoor unit. In the present embodiment, one first containeris provided for each outdoor unit. The first containeris disposed at a position in which the air flow generated by the blower(air flow generated by the outdoor unit) reaches.

One first containermay be provided for the plurality of outdoor units. In this case, the first containeris disposed at a position in which the air flow generated by the plurality of outdoor unitsreaches.

In a plan view, the first containerhas a substantially U-shape. The first containeris disposed along the heat exchanger. In other words, the first containeris disposed along three side surfaces of the casing, in which the heat exchangeris disposed (that is, three side surfaces in which the intake portis formed). The first containeris disposed on an upstream side of the heat exchangerin a flow direction of the air flow generated by the outdoor unit. In the first container, the air flow of the air sucked from the intake portinto the casingby the driving of the blowerreaches.

The first containerhas air permeability. Therefore, when the bloweroperates, air enters the adsorbent accommodated in the first container, or the air inside the adsorbent accommodated in the first containeris discharged. That is, the air inside the first containercan be replaced with the outside air by the operation of the blower.

The first adsorbent pipeconnects the plurality of first containersto the separation device. The first adsorbent pipetransports the adsorbent between the plurality of first containersand the separation device. For example, a material of the first adsorbent pipeis polyvinyl chloride, a metal such as aluminum or stainless steel, or the like. The cross-sectional shape of the first adsorbent pipemay be circular or rectangular.

The first adsorbent pipeincludes a first pipethat transports the adsorbent from the separation deviceto the plurality of first containers, and a second pipethat transports the adsorbent from the plurality of first containersto the separation device.

The first pipeincludes a main pipe portionand a plurality of branch pipe portionsthat branch off from the main pipe portionThe main pipe portionis disposed between the outdoor unitin the first row and the outdoor unitin the second row. One end of the branch pipe portionis connected to the main pipe portionThe other end of the branch pipe portionis connected to the upper part of the first container. The adsorbent is transported from the separation deviceto the upper part of the first containervia the main pipe portionand the branch pipe portionand then into the first container. In the first container, the adsorbent is transported from the upper side to the lower side.

The second pipeincludes a main pipe portionand a plurality of branch pipe portionsthat branch off from the main pipe portionThe main pipe portionis disposed between the outdoor unitin the first row and the outdoor unitin the second row. One end of the branch pipe portionis connected to the main pipe portionThe other end of the branch pipe portionis connected to the lower part of the first container. The adsorbent is discharged from the lower part of the first containerand is transported to the separation devicevia the main pipe portionand the branch pipe portion

As shown in, the first pipeis disposed above the second pipe. Each of the first pipeand the second pipeis inclined to extend downward as it moves toward a downstream side in a transport direction of the adsorbent. That is, the first pipeis inclined to extend downward as the first pipeis separated from the separation device, and the second pipeis inclined to extend downward as the second pipeapproaches the separation device. The adsorbent moves through the first pipeand the second pipeby its own weight. For example, the adsorbent moves by rolling along the first pipeand the second pipe. Depending on the size of the adsorbent or the like, a roller conveyor, belt conveyor, blower, or the like for assisting the movement of the adsorbent may be provided in the first pipeand the second pipe.

The separation devicehas a function of separating carbon dioxide from the adsorbent that has adsorbed carbon dioxide. The separation devicetransports the adsorbent which has adsorbed carbon dioxide in the plurality of first containersthrough the first adsorbent pipe(the second pipe). The adsorbent from which the carbon dioxide has been separated by the separation deviceis transported to the plurality of first containersthrough the first adsorbent pipe(first pipe).

The separation devicemay include a heater, and may separate carbon dioxide by heating (for example, 60° C. to 120° C.) the adsorbent. The heating temperature may be appropriately changed depending on the specific material of the adsorbent. Alternatively, the separation devicemay separate carbon dioxide by including a vacuum pump and placing the adsorbent under a reduced pressure condition.

The recovery deviceis connected to the separation devicethrough a recovery pipe. The carbon dioxide separated by the separation deviceis transported to the recovery devicethrough the recovery pipe. The recovery devicerecovers the carbon dioxide separated by the separation device.

The recovery devicehas, for example, a methanation system having a function of generating methane using carbon dioxide, hydrogen, water, electric power, and the like. The recovery devicemay include a gas cylinder capable of storing carbon dioxide.

The renewable energy deviceincludes solar panelsand. For example, the solar panelsandare lightweight and flexible film-type solar panels. As shown by the dotted arrow in, power generated by the renewable energy deviceis supplied to at least one of the plurality of outdoor units, the separation device, and/or the recovery device.

The solar panelis attached to a wall surface of the separation device. The solar panelis attached to a wall surface of the recovery device. As a result, it is not necessary to newly provide space for installing the solar panelsand, thereby improving space efficiency. To increase the installation area of the solar panelsand, the solar panelsandmay be attached to the wall surface of the separation deviceor the recovery devicethat has a larger area. In addition, to improve the power generation of the solar panelsand, the separation deviceor the recovery devicemay be disposed such that the wall surface to which the solar panelsandare attached faces south.

The number of each component installed in the carbon dioxide recovery systemwill be described.

The number of first containersis greater than the number of separation devices. Additionally, when the number of methanation systems in the recovery deviceis denoted by N, the number of separation devicesis denoted by N, and the number of outdoor unitsis denoted by N, the relationship N≤N<Nis satisfied.

For example, in the present embodiment, the number of first containersis 6, the number Nof methanation systems is 1, the number Nof separation devicesis 1, and the number Nof outdoor unitsis 6. Note that the number of outdoor units, the number of first containers, the number of separation devices, and the number of methanation systems are not limited to this. The number of first containersmay be larger than the number of separation devices, and may satisfy the relationship N≤N<N. In addition, when one first containeris provided for the plurality of outdoor units, the number of outdoor unitsis greater than the number of first containers.

A method of recovering carbon dioxide using the carbon dioxide recovery systemwill be described.

The carbon dioxide recovery systemrecovers carbon dioxide by utilizing the air flow generated by the blowerand the external air blown into the first container.

That is, when the bloweris driven, the air flow of the air sucked from the intake portinto the casingreaches the first container. In addition, the external air is blown into the first container. The air flow generated by the blowerand the external air are brought into contact with the adsorbent accommodated in the first container, causing the adsorbent to adsorb carbon dioxide (adsorbing step). After that, the adsorbent which has adsorbed the carbon dioxide is transported from the first containerto the separation device. The separation deviceseparates carbon dioxide from the adsorbent which has adsorbed carbon dioxide (separation step). The recovery devicerecovers the carbon dioxide separated by the separation device(recovering step).

As described above, the carbon dioxide recovery systemaccording to the present embodiment includes a plurality of outdoor unitsof an air conditioning system; an adsorbent that is configured to adsorb carbon dioxide; a plurality of first containersthat are disposed at positions in which at least part of an air flow generated by the plurality of outdoor unitsreaches, that are configured to accommodate the adsorbent therein, and that have air permeability; a separation devicethat is connected to the plurality of first containersand that is configured to separate carbon dioxide from the adsorbent which has adsorbed the carbon dioxide; and a recovery devicethat is configured to recover the carbon dioxide separated by the separation device. The number of the plurality of first containersis greater than the number of the separation devices.

As a result, carbon dioxide can be recovered by utilizing the air flow generated by the plurality of outdoor units. Therefore, carbon dioxide can be recovered with energy savings (less energy), improving the efficiency of recovering carbon dioxide.

In this case, it is necessary to recover carbon dioxide while preventing a decrease in the capacity of the air conditioning system. That is, in a case in which the amount of adsorbent accommodated in the first containeris large, the air volume passing through the outdoor unitdecreases due to the pressure loss caused by the adsorbent, potentially reducing the air conditioning capacity of the air conditioning system. In the present embodiment, a plurality of first containersare provided, and the amount of adsorbent accommodated in one first containeris set to be within a range that does not cause a decrease in air volume. In addition, since the adsorption time of carbon dioxide in one first containeris shortened, the number of first containersis set to be larger than the number of separation devices, and the adsorption time of carbon dioxide in the plurality of first containersand the separation time of carbon dioxide by the separation devicesare set to be substantially equal. As a result, the adsorption and separation of carbon dioxide can be performed with a good balance while suppressing the decrease in the capacity of the air conditioning system, thereby improving the efficiency of recovering carbon dioxide.

In addition, the recovery deviceincludes a methanation system that generates methane using the carbon dioxide separated by the separation device. When the number of methanation systems is denoted by N, the number of separation devicesis denoted by N, and the number of the plurality of the outdoor unitsis denoted by N, the relationship N≤N<Nis satisfied.

When methane is generated in the methanation system, a large amount of carbon dioxide is required. By satisfying the relationship N≤N<N, the generation of methane in the methanation system can be carried out efficiently.

In addition, when the number of the plurality of outdoor unitsis increased, the air flow rate generated by the plurality of outdoor units(that is, the air flow rate that comes into contact with the adsorbent accommodated in the first container) also increases. Therefore, the amount of carbon dioxide adsorbed by the adsorbent increases, and the efficiency of recovering carbon dioxide improves.

In addition, among four side surfaces of the casing, the plurality of outdoor unitsare disposed such that the side surfaces with the smallest area in which the heat exchangeris disposed face each other.

As a result, it is possible to suppress the interference of the air flows generated by the plurality of outdoor unitswith each other. Therefore, it is possible to recover carbon dioxide while suppressing the decrease in the capacity of the air conditioning system.